DIY LED strip stairs

[designabc123]

Designabc - I think what you've drawn should work using those pir sensors.

Sorry to confuse you with my comment. Before I saw and posted that particular sensor, I was thinking that a typical sensor might have its 0v (black) connection common between its power in and its switched output, in which case linking the black 'in' and 'out' of both sensors means you can do without the second black wire going up the stairs! But I don't know if that is true for this particular sensor, so best to stick with your wiring.

You will need to work out, from the total length of led strip you need, and it's current draw, what the current rating for the psu should be.

Best wishes for the project

Thanks for clarifying, I think I know what you mean, as if I had the 240V PIR sensor there would have been three cables (one being shared), but I think that the 12V one needs 4 cables.

I will test out the setup "on flat ground" first to see if it actually works and share the results, in case anyone will be interested in this setup in the future.

Regarding the PSU, I have a kit that came with 15m of strip LED lights and included the PSU. I assume that their included PSU should be able to power all the LEDs, as it's in the same package. But because I'm adding the two PIR sensors, do you think that will require a higher rated PSU?

 

[Avo Mk8]

The current draw of the sensors is likely to be small in the grand scheme of things. I think you will be fine using the psu you have.
(if you have, or can borrow, a multimeter, you could check what current a sensor takes - I imagine only a few 10's of mA, if that)

 

[designabc123]

The current draw of the sensors is likely to be small in the grand scheme of things. I think you will be fine using the psu you have.
(if you have, or can borrow, a multimeter, you could check what current a sensor takes - I imagine only a few 10's of mA, if that)

That's great, I do have a multimeter and will measure the sensor's take. Thanks so much for helping out!
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That's great, I do have a multimeter and will measure the sensor's take. Thanks so much for all your help!

 

[Lucien Nunes]

Agree with most of the above. The PIR will normally only be switching one pole of the supply, therefore the other will be common between input and output. Running up the stairs will be three conductors - feed, switched feed and common, with each strip tapped into switched and common of the main run and all three terminating at the far PIR. Note that some electronic LED controls switch the negative, which would make the common the positive.

You can see some of my ideas about tapping a small 12V cable neatly into a run in posts #12 & #15 here:
Tapping into a run

 

[designabc123]

Thanks for the reply Lucien, unfortunately I don't have access to your post. I'm probably too new on the forum.

 

[designabc123]

Good news everyone, the setup with the two PIR sensors and the LED strips connected in parallel worked. The only small thing that is not ideal is the fact that when the second sensor is triggered after the first one already turned the lights on, the LEDs closer to the second sensor become a bit brighter. I imagine that as the voltage drops a bit from the first LED to the last, triggering the second sensor while the lights are already on reverses the direction of the power (the last LED gets power first). It's not a huge difference and I can definitely live with this setup. Thanks to everyone for your guidance.

 

[Avo Mk8]

Hi designabc
if you were to use thicker red & black power wires up to the top sensor, or maybe try another pair of wires in parallel, you might lessen the effect you mention.
Pleased to hear it's all working.

 

[designabc123]

Hi designabc
if you were to use thicker red & black power wires up to the top sensor, or maybe try another pair of wires in parallel, you might lessen the effect you mention.
Pleased to hear it's all working.

Thanks for the tip! It's a very slight difference and I've already done so much with this setup as it's not worth removing the old wire and doing it again, but I'll definitely know for my next PIR + LED project.